Synthetically produced precipitated silicas have for many years played an important role as a component part of toothpaste agents. They are very pure, toxicologically satisfactory and compatible with the other component materials of toothpastes, such as for example glycerin, sorbitol, thickening agents, detergents, coloring and fragrance materials and, optionally, soluble fluoride compositions.
Synthetic precipitated silicas are produced by precipitation from alkaline silicate solutions with acids, along with stirring and filtering out of the suspension, washing, drying and comminuting. The precipitating process allows the possibility of predetermining important properties such as the particle diameter, particle shape and particle density and/or hardness, simply by treatment in the flocculating phase.